As the detection and ranging apparatus, for example, an in-vehicle radar (hereinafter, a radar apparatus is taken as a specific example of the detection and ranging apparatus), there is an apparatus in which a technology is adopted in which a transmission sensor array including a plurality of transmission sensor elements is combined with a reception sensor'array including a plurality of reception sensor elements to effectively enlarge an aperture of the reception sensor array, thereby realizing a downsized apparatus without sacrificing the performance. This technology is called “holographic aperture synthesis system”, “holograph”, “aperture synthesis”, and so on. The radar apparatus using the aperture synthesis radiates probe signals from the plurality of transmission sensor elements (by any one or a combination of a time-division multiplexing system, a frequency division multiplexing system, and a code division multiplexing system). The radar apparatus then receives, by the plurality of reception sensor elements, echo signals generated, by reflecting the probe signals by a target to be detected. The radar apparatus then synthesizes the signals received by the respective reception sensor elements to increase the number of effective reception sensor elements, thereby increasing the number of detectable targets, and also improving an angular resolution capability. In the following description, the radar apparatus using the aperture synthesis is referred to as “synthesis aperture radar”. Further, the sensor elements are used without any distinction from antennas (elements), and the sensor array is used without any distinction from an array antenna.